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Background
The angle-dependent torque capacity of the subtalar pronators and supinators is important to maintain dynamic ankle stabilisation. Based on the peak torques during maximum voluntary isometric pronation and supination across the subtalar range of motion, the strength curves of younger and elderly males and females were investigated.

Methods
Maximum voluntary isometric subtalar pronator and supinator strength tests were administered to 30 younger and 30 elderly volunteers (each 15 male and 15 female subjects). Total active subtalar range of motion and peak pronator and supinator torques were measured in five anatomical subtalar joint angles using a custom-built apparatus with two force transducers. Furthermore, relative torques (normalised to the individual peak torque) and pronator-to-supinator strength-ratios were also calculated.

Results
Pronator-to-supinator strength ratio, and peak pronator and supinator torques are affected by age and by joint angle x age interactions. All supinator strength curves show a steadily descending characteristic from the pronated to the supinated positions. The pronator strength curve had an inverted U-shaped characteristic, except for younger women of whom 47 % exert highest peak values in the end-range pronation angle. Both relative pronator and supinator strength are dependent on sex (P < 0.05). Relative pronator strength is also affected by joint angle x sex (P < 0.0001) and joint angle x sex x age (P < 0.05) interactions. Beside age effects on all range of motion parameters, pronation range of motion is influenced by a sex x age interaction (P < 0.05).

Conclusions
Age- and sex-related differences in both subtalar strength profile and range of motion have to be considered when testing strength across subtalar range of motion. Younger females have higher pronator strength capacity in the most pronated joint angle, which may be due in part to their greater subtalar joint range of motion compared to the other groups. In the most supinated position both pronator and supinator strength capacity is reduced in younger females compared to younger males.

The movement axis was orientated corresponding to the subtalar joint axis deviating about 23? to medial and about 41? to dorsal from the longitudinal foot axis [15]

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There are massive standard deviations about those means in reference 15 that they based the position of their movement axis on. Shame that they did not position the axis of the apparatus in the same position as the individuals axis rather than that reported mean. That would have generated some clinically useful data - which the authors did acknowledge

A further limitation of the study is that our subtalar testing device has the same axis position for all participants. It has to be mentioned here that variations in the spatial orientation of the subtalar joint axis and other foot axes were found both within the population and in dynamic movements

There are massive standard deviations about those means in reference 15 that they based the position of their movement axis on. Shame that they did not position the axis of the apparatus in the same position as the individuals axis rather than that reported mean. That would have generated some clinically useful data - which the authors did acknowledge

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so I guess we wait until the next study, the title of the tread looked promising

BACKGROUND: It is currently unclear how participation in different sports affects the angle-specific subtalar pronator and supinator muscle strength and pronator-to-supinator strength ratio (PSR). OBJECTIVE: Based on the hypothesis that both differences sport-related patterns of play and foot-ground interaction may lead to sport-specific muscle adaptations, this study compared the angle specific pronator and supinator strength capacity of handball and soccer players. METHODS: Eighteen healthy male handball and 19 soccer players performed maximum isometric voluntary isometric contractions using a custom-made testing apparatus. Peak pronator (PPT) and supinator torques (PST), pronator and supinator strength curves (normalised to the peak torque across all joint angles) and PSR were measured in five anatomical joint angles across the active subtalar range of motion (ROM). RESULTS: All analysed parameters were dependent on the subtalar joint angle. The ANOVA revealed significant `joint angle' ? `group' interactions on PPT, pronator strength curves and PSR. No group differences were found for active subtalar ROM. CONCLUSION: In previously uninjured handball and soccer athletes, there were intrinsic differences in angle-specific subtalar pronator muscle strength. The lower PSR, which was found in the most supinated angle, can be seen as a risk factor for sustaining an ankle sprain.